A borehole muon detector for muon radiography or geotomography is provided, the borehole muon detector including a substantially cylindrical housing, which defines a bore, a pair of end caps, each end cap sealing an end of the cylindrical housing and a plurality of sealed drift tubes which are longitudinally disposed in the bore of the housing to form a bundle of drift tubes, wherein each sealed drift tube comprises: a centrally located anode wire disposed on a longitudinal axis; an inner surface which is coated with a cathode coating, the cathode coating divided into a first cathode pad and a second cathode pad by a Vernier pattern; and a timer in electrical communication with the anode wire for measuring a drift time. A system and a method are also provided.